Hindered isothiocyanates, and the method of preparing the same



3,322,8i Patented May 30, 1196? 3,322,810 HENDERED ISOTHIOCYANATES, AND THE METHOD OF PREPARING THE SAME John F. ()lin, St. Louis, Mo., assignor to Monsanto Comparty, a corporation of Delaware No Drawing. Filed Sept. 19, 1963, Ser. No. 310,121 11 Claims. (Cl. 260-454) This invention relates in general to certain new and useful improvements in isothiocyanates, and more particularly, to a new group of alkylated aryl isothiocyanates, diisothiocyanates, and to a new and improved method of preparing the same.

It is the primary object of the present invention to provide a class of alkylated isothiocyanates and alkylated diisothiocyanates.

It is another object of the present invention to provide a method of preparing alkylated isothiocyanates and alkylated diisothiocyanates.

It is a further object of the present invention to provide a method for producing hindered isothiocyanates and diisothiocyanates and thereby reduce the reactivities of such compounds.

It is also an object of the present invention to provide a class of compounds of the type stated, which are inexpensive to manufacture, and which can be produced from readily available starting reagents.

With the above and other objects in view, my invention resides in the novel features and form, and arrangement of the various elements presently described.

Generally speaking, the present invention resides in a discovery that it is possible to selectively hinder the reactivities of isothiocyanates and diisothiocyanates by introducing alkyl groups and halogen atoms in positions which are ortho to the isothiocyanate radicals. Moreover, the desired degree of hindrance can be attained by selecting various alkyl groups for attachment to the ortho-positions.

More particularly, a major facet of the present invention resides in the discovery that alkylated phenyl isothiocyanate compounds containing a tertiary alkyl group in each of the ortho-positions with respect to the isothiocyanate radical, provide a maximum amount of obtainable hindrance. A somewhat ilesser amount of hindrance is obtained if one of the ortho-positions is provided with a tertiary alkyl radical and the other ortho-position is provided with a radical selected from the class consisting of primary and secondary alkyl radicals, and halogen atoms. A moderate amount of hindrance is obtained when the first ortho-position is provided with a tertiary alkyl radical and the second ortho-position contains hydrogen, or when the first and second ortho-positions are provided with primary or secondary alkyl radicals. A slight degree of hindrance is obtained when the first ortho-position is provided with a primary or secondary alkyl radical and the second ortho-position is provided with hydrogen.

Substitution of the phenyl isothiocyanates in the metaposition or in the para-position by alkyl groups or halogen atoms does not produce hindrance of the isothiocyanate radical and the present application is not concerned with compounds of these latter classes. However, included within the scope of the present invention are those compounds which have alkyl or halogen substitution in the meta or para-positions in combination with substitution in the ortho-position.

As used herein, the term hindrance refers to the lack of chemical reaction from the isothiocyanate function and is explained by the shielding spatial arrangement of particular atomic groupings (alkyl radicals) which inhibit its natural reaction.

In accordance with the present invention, it is possible to provide hindered isothiocyanates of the general formula which are formed by reacting a hindered aniline with carbon disulfide, according to the following reaction The reaction will take place readily in the absence of a catalyst at elevated temperatures within the range of C. to 300 C. It is possible to complete the reaction at temperatures as low as 80 C. but the reaction time must be extended considerably to give completeness of reaction. Actually an intermediate dithiocarbamic acid is formed, which breaks down to render the hindered isothiocyanate according to the reaction:

@nrn. Get

When the original aniline is ortho-alkyl substituted, the decomposition of the dithiocarbamic acid is immediate at the temperatures employed and, therefore, no heavy metal salt addition such as mercury salts is required.

The alkyl substituted aniline is added to a flask and heated under a reflux condenser to the reaction temperature usually 180 C. Carbon disulfide is then added slowly and continuously in a dropwise manner. Where slightly and moderately hindered anilines are employed as the reactants, the reaction with carbon disulfide is very rapid at the beginning thereof, due to the formation of a substituted thiocarbanilide, according to the following reaction:

Thereafter, the reaction rate is considerably reduced due to a thiocarbanilide dissociation, according to the following reaction:

Where strongly hindered anilines are employed as initial reactants, the intermediate thiocarbanilides thus formed in the reaction, are not stable at the reaction temperatures and in the presence of the carbon disulfide. With the accompanying evolution of hydrogen sulfide, the reaction proceeds at a rate determined by the concentration of the unchanged alkyl aniline. The dissociation of the intermediate thiocarbanilide, as in the case of the lesser hindered anilines, is not the rate determining factor. The reaction of the hindered amines with carbon disulfide is not an instantaneous reaction. Since carbon disulfide is a fairly volatile material, having a boiling point of 46.3 C., the rate of addition of the carbon disulfide should approximate its rate of reaction with the aniline reactant. If this condition is not met, the cooling condenser will cause accumulation of carbon disulfide in the reaction vessel thereby causing a temperature drop and a lowering of the rate of reaction.

Various alternative modes of reaction investigated did not produce the degree of conversion and were not as successful as the above-mentioned procedure. Two modes of reaction, which were moderately successful, involved nounced than when placed in the paraor meta-positions. The effects vary with the type and degree of substitution. When phenyl isothiocyanate is substituted in the orthoposition, the degree of hindrance may be shown in the the passing of alkylated aniline and carbon disulfide vapors 5 following table with substitution of various alkyl radicals.

TABLE I Unhindered Slightly Hindered Hindered Strongly Hindered Very Strongly I'Ilndered Phenyl Isothioeyauate Z-methylphenyl isothiocya- 2,6-d1methylphenyl isothio- 2-tertiary-butyl-fi-methyl- 2,6-ditertiarybutylphenyl 1nand p-methylphenyl nate eyanate phenyl isothiocyanate isothiocyanate isothiocyanates 2-ethylphenyl isothiocya- 2,6-d1ethylphenyl isothio- 2-tertiary-butyl-G-ethylphenmand p-ethylphenyl isonate eyanate yl isothiocyanate thtoeyanate 2-isopropylphenyl isothio- 2,t-di-1sopr0pylphenyl 2-tertiary-butyl-fi'isopropylmand p-isopropylphenyl cyauate isothiocyanate phenyl isothiocyanate isothiocyanate 2-tertiar y-butylphenyl 1S0- cyana e through a heated zone within the temperature range of 250 to 400 C. or heating the two reactants in an autoclave under pressure to a temperature within the range of 180 to 250 C. When these latter two procedures were employed, the results obtained were not nearly as good as the results when the first-mentioned procedure was employed due to the reverse reaction set forth below.

The procedure of the present invention avoids this reverse reaction, since the hydrogen sulfide which is thus formed, is eliminated almost as fast as it is produced. Due to the substantial partial pressure of the carbon disulfide in the reaction vessel, the evolved hydrogen sultide is saturated by this reactant. The carbon disulfide may be recovered by any conventional practice, such as by scrubbing the vent gases by a suitable organic solvent, by chilling at low temperatures, or by liquefaction and fractional distillation.

The alkylation of the primary aromatic amines is more fully described in my copending application, Ser. No. 266,023, filed Mar. 18, 1963, therefore, the method of preparation of the starting aniline material is not described in detail herein.

In the hindered isothiocyanates described above, R is selected from the class consisting of chlorine and bromine, fluorine, iodine and any alkyl radical up to and including carbon atoms; and R is a tertiary alkyl of 4 through 10 carbon atoms. Included within the class of alkyl radicals are methyl, ethyl, isopropyl, normal propyl, normal butyl, isobutyl, tertiary butyl, normal pentyl, isopentyl, and tertiary pentyl, tertiary octyl, etc.

It has been found in connection with the present invention, that the spatial size of the attached alkyl radical determines the amount of hindrance obtained. Moreover, the position in which attached to the phenyl radical also determines the amount of hindrance obtained. Halogen atoms, or alkyl radicals attached in the para-position or meta-positions provide little or no hindrance and do not materially affect the reactivity of the phenyl isothiocyanate.

When chlorine or bromine are attached at the orthopositions, such as in 2,6-dichlorophenyl isothiocyanate, a very slight amount of steric hindrance is obtained. A slightly hindered compound is also obtained when only one R group is a methyl, ethyl or isopropyl. Moderate hinderance is obtained when R and R are methyl, ethyl, or normal propyl radicals. However, strong hindrance is obtained when at least one R is a tert-butyl or tert-pentyl group. Very strong hindrance is obtained when both R and R are tert-alkyl of 4 to 10 carbon atoms. Thus, it can be seen that when alkyl groups are placed in the ortho-position, the effects are considerably more pro- The steric effects resulting from the alkylation of the phenyl isothiocyanates, especially in the ortho-positions, are reflected in the physical properties of the product, such as the electronic spectra, molecular refractions, dipole moments, bond links and valency angles. The steric effects are particularly noted in the chemical properties, such as reaction rates and in miscellaneous properties such as melting points of derivatives, boiling points, heats of combustion, infra-red spectra, raman spectra, phosphorescence and fluorescence, polargraphic behavior, stability of radicals and biological activity.

By reacting the proper ortho substituted aniline with carbon disulfide, it is possible to obtain the following hindered phenyl isothiocyanates: Z-methyl, Z-ethyl, 2- 'normal-propyl, 2-isopropyl, Z-prirnary-butyl, 2-seconda1ybutyl, Z-tertiary-butyl, 2-primary-pentyl, 2-secondarypentyl, Z-tertiary-pentyl; 2,6-dimethyl; 2,6-di-etl1yl; 2,6-diisopropyl; 2,6-di-primary-butyl; 2,6-di-secondary-butyl; 2,6-di-tertiary-butyl; 2,6-di-primarypentyl; 2,6-di-secondary-pentyl; -2,6-di-tertiary-pentyl; etc. phenyl isothiocyanates.

I It is, of course, possible to attach different alkyl radicals in each of the ortho-positions to obtain compounds such as 2-methyl-6-ethyl; 2-methyl-6-ispropyl; 2-ethyl-6-isopropyl; 2-isopropyl, G-secOndary-butyl; etc. phenyl isothiocyanate.

v Alkyl substituted phenyl isothiocyanates of the following general formulae:

can be produced by reacting like alkyl substituted anilines with carbon disulfide in accordance with the above general reaction. The reaction for these last four illustrated compounds also takes place readily in the absence of a catalyst within the temperature range of 180 C. to 300 C. It is also possible to complete the reaction at temperatures as low as C. but, again, the reaction time must be extended considerably. An intermediate dithiocarbamic acid also forms and immediately breaks down to render the hindered isothiocyanate. The general reactions which take place in the production of each of these compounds are:

lla

NH; CS2

R R S I NH CS:

I H SH 2 Some of the reactants are 2,3,4-trimethylaniline; 2,4,5- trirnethylaniline; 2,3,6-trimethylaniline; 2,4,6-trimethylaniline; 2,3,4-triet11ylani1ine; 2,4,5-triethylaniline; 2,3,6- triethylaniline; 2,4,6 triethylaniline; 2,3,4 triisopropylaniline; 2,4,S-triisopropylaniline; 2,3,6-triisopropylaniline; 2,4,6 triisopropylaniline; Z-methyl-3,4-diethylaniline; 2- methyl-3,6-dimethylaniline; 2 methyl-4,6-diethylanaline; 2-methyl-3-ethyl 4 secondary-butylaniline; 2,3-diisopropyl-6-secondary-butylaniline; and 2-methyl-4-ethyl-6- secondary-pentylaniline.

The reaction products thus obtained are 2,3,4-trimethylphenyl isothiocyanate; 2,4,5 trimethylphenyl isothiocyanate; 2,3,6-trimethylphenyl isothiocyanate; 2,4,6-trimethylphenyl isothiocyanate; 2,3,4-triethylphenyl isothiocyanate; 2,4,5-triethylphenyl isothiocyanate; 2,3,6-triethylphenyl isothiocyanate; 2,4,6-triethylphenyl isothiocyanate; 2,3,4-triisopropylpheny1 isothiocyanate; 2,4,5-triisopropylphenyl isothiocyanate; 2,3,6 triisopropylphenyl isothiocyanate; 2,4,6-triisopropylphenyl isothiocyanate; 2-methyl- 3,4 diethylphenyl isothiocyanate; 2-methyl-3,6-diethylphenyl isothiocyanate; 2-methyl-4,6-diethylphenyl isothiocyanate; 2-methyl-3-ethy1-4-secondary butylphenyl isothiocyanate; 2,3-diisopropy1-6-secoudary-butylphenyl isothiocyanate; and 2 methyl-4-ethyl,6-secondary-pentylphenyl isothiocyanate.

Inasmuch as the spatial size of the alkyl radical in the ortho-positions determines the degree of hindrance, it has been found that when one or both of the alkyl radicals are tertiary alkyls such as tertiary butyl, tertiary amyl or tertiary heXyl, etc., strong hindrance is obtained. By further reference to Table I, it can be seen that one tertiary alkyl group in anortho-position renders a degree of hindrance which is equal to, or greater than, the hindrance obtained with two primary or two secondary alkyl groups in ortho-positions. In fact, there is a very considerable increase in the degree of hindrance obtained when comparing a secondary alkyl with a tertiary alkyl. For example, 2,6-di-sec-butylphenyl isothiocyanate is a moderately hindered compound, whereas 2,6-di-tert-butylphenyl isothiocyanate is a very strongly hindered compound.

It is possible to produce hindered diisothiocyanates of the following general formula:

4 a Re where R R R R R R R and R are selected from the class consisting of hydrogen, halogen atoms or alkyl radicals of from 1 to 10 carbon atoms. If the product is not a hybrid product at least one R ortho to the isothiocyanate radical on each of the phenyl rings in the above formula must be an alkyl group, either primary, secondary or tertiary, when the remaining RS on each of the phenyl groups are hydrogen or halogen atoms. Preferably at least R and either R or R is a tertiary alkyl group. For hybrid hindrance it is preferable that R is a tertiary alkyl group. If one of the phenyl groups is provided with no alkyl group or halogen atom in the ortho-position, then R and R must be provided with alkyl groups. Depending upon the type of substitution obtained, the two isothiocyanate groups may possess similar or greatly different degrees of reactivities, For eX- ample, if R and R are tertiary alkyl radicals, and R and R are hydrogen atoms, the former isothiocyanate radical is greatly hindered, whereas the latter isothiocyanate radical is completely unhindered.

In order to obtain the hindered diisothiocyanate of the present invention, it is necessary to alkylate the starting aniline material in the desired positions in the manner as described in my aforementioned copending patent application. If it is desired to form hybrid hindered diisothiocyanates, equal molar quantities of alkylated and unalkyl ated aniline will be reacted. For example, if it is desired to form 2,6-isopropyl-4,4'-methylenebis (phenyl isothiocyanate), equal molar quantities of 2,6-isopropylaniline and aniline would be reacted with a formaldehyde, or a substance which is capable of rendering formaldehyde upon hydrolysis, thereby chemically bonding the 2 aniline radicals at the 4 and 4 positions through a methylene radical. Some of the compounds which are capable of rendering formaldehyde upon hydrolysis and which are suitable for use in the present invention, are paraformaldehyde, trioxymethylene, and methallyl. The reaction preferably takes place in the presence of a catalyst such as hydrochloric acid, phosphoric acid, hydrobromic acid or hydroiodic acid. Carbon disulfide is then added to the dianiline compound and heated to within the range of C. to 300 C. for converting the dianiline to a diisothiocyanate. If the dianiline compound is a solid, it may be dissolved in a suitable inert solvent such as chlorobenzene or high boiling ethers such as diethylene glycol and dimethyl ether for the reaction. I

The degree of hindrance obtained when diisothiocyanates of the formula:

R R I I in R are alkylated in the ortho-positions is recorded in the following table.

TABLE 2 Very strongly hindered, R -R are tert-alkyl (4-10 carbon atoms).

Strongly hindered, R and R are tart-alkyl; R and R are primary or secondary alkyls of 1-4 carbon atoms. Moderately hindered, R -R are primary or secondary alkyl; or R and R are tert-alkyl and R and R are hydrogen.

Pure strong hybrid hindrance, R is a tert-alkyl; R is a tert-alkyl or primary or secondary alkyl; R and R are hydrogen.

Pure moderate hybrid hindrance, R and R are primary or secondary lower alkyls; R and R are hydrogen. R is a tert-alkyl and R R and R are hydrogen.

Strong-moderate hybrid hindrance, R is a tert-alkyl; R is a tert-alkyl or primary or secondary alkyl; R and R are primary or secondary alkyls. R and R are tertalky-l; R is a tert-alkyl or primary or secondary alkyl; and R is hydrogen.

Strong-weak hybrid hindrance, R is a tert-alkyl; R is a tert-alkyl; R is hydrogen; and R is methyl or ethyl.

Moderate-weak hybrid hindrance, R and R are methyl or ethyl; R is hydrogen; and R is methyl or ethyl. R is a tert-alkyl; R is methyl or ethyl; R and R are hydrogen.

The hindered diisothiocyanates of the present invention are readily formed by reacting suitable combinations of alkylated anilines with formaldehyde in the presence of a suitable catalyst, above mentioned, according to the following reaction:

I Q-NH, HCHO The reaction for producing diisothiocyanates takes place within the same temperature range as the reaction for producing monoisothiocyanates and under the same general conditions. An intermediate dithiocarbamide is formed and which immediately breaks down to render the hindered diisothiocyanate according to the following reaction:

Some of the dianilines formed by reacting the ortho alkylated monoaniline-s listed above with formaldehyde are 4,4'-methylenebis 2,6-dimethylaniline); 4,4-methylene'bis (2,6-diethylaniline) 4,4'-methylenebis 2,6-diisopropylaniline); 4,4'-methylenebis( 2,6-di-sec-butylaniline); 4,4-methylenebis Z-ethyl, 6-methylaniline) 4,4'-methylenebis 2-tert-butyl, 6-methylaniline) 4,4-methylenebis(Z-ethyl, 6-isopropy1aniline 4,4-methylenebis 2-prirn'ary 'butyl, 6-isopropylaniline 4,4-methylenebis(Z-tert-butyl, 6-ethylaniline) etc.

Some of the dianiline compounds which are used in the preparation of the hybrid diisocyanate compounds are:

The hindered diisothiocyanates which are produced from the above listed dianilines alkylated in the orthopositions are:

The hindered hybrid diisothiocyanates which are formed from the hybrid dianilines listed above, are:

2,6-dimethyl-4,4'-methylenebi-sphenyl isothiocyanate;

2,6-diethyl-4,4'-methylenebisphenyl isothiocyanate;

2,6-diisopropyl-4,4'-methylenebisphenyl isothiocyanate;

2,6-di-normal-butyl-4,4-methylenebisphenyl isothiocyanate;

2,6-di-tert-butyl-4,4-methylenebisphenyl isothiocyanate;

2-tert-butyl-6-methyl-4,4'-methylenebisphenyl isothiocyanate;

2-ethyl-6-methy'l-4,4'-n1ethy1enebispheny1 isothiocyanate; 2-ethyl-6-isopropyl-4,4'-rnethylenebisphenyl isothio cyanate; 2-n-butyl-6-n-propyl-4,4-rnethylenebisphenyl isothiocyanate; 2-n-butyl-6tert-butyl-4,4'-1nethylenebisphenyl isothiocyanate; etc.

All of the above hindered compounds including both the hindered phenyl isothiocyanates and the hindered phenyl diisothiocyanates have the same utility as their counterparts, namely the unhindered phenyl isothiocyanates and the unhindered phenyl diisothiocyanates respectively. The isothiocyanates and diisothiocyanates have found substantial use in the chemical industry in the fields of pesticides and particularly vulcanization accelerators. Various i-sothiocyanates and diisothiocyanates have found particular uses as pickling inhibitors. The hindered phenyl isothiocyanates and hindered phenyl diisothiocyanates exhibit the same utility, that is, they are also useful as pesticides, vulcanization accelerators and pickling inhibitors. It is well known, that the isothiocy-anates and diisothiocyan'ates react vigorously with other substances such as alcoholic ammonia and, therefore, these compounds have created a large number of control problems. Moreover in many cases, the unhindered compounds cannot be employed for the desired purpose because of the high rates of reactivity. In accordance with the present invention, it is therefore possible to selectively hinder these phenyl isothiocyanates and phenyl diisothiocyanates so that they exhibit a desired reactivity, and therefore eliminate many of the commercial control problems heretofore encountered.

It is also possible to provide hindered isothiocyanate-s and diisothiocyanates with combinations of halogens and alkyl groups on the phenyl radical. Such compounds are, for example:

3-chloro-2,G-dimethylphenyl isothiocyanate; 4-chloro-2,6-dimethylphenyl isothiocyanate; 3-chloro-2,6-diethylphenyl isothiocyanate; 4-chloro-2,6-diethylphenyl isothiocyanate; 3-bromo-2,6-dimethylphenyl isothiocyanate; 4-bromo-2,6-dimethylphenyl isothiocyanate; 3-brorno-2,6-diethylphenyl isothiocyanate; 4-bromo-2,6-diethylpheny1 isothiocyanate; 3-chloro-2,6-di-n-propylphenyl isothiocyanate; 4-bromo-2,6-di-isopropylphenyl isothiocyanate; 3-'bromo-2,6-di-primary butylphenyl isothiocyanate; 2,6-di-secondary butyl-4-chlorophenyl isothiocyanate; 3-bromo-2,6-di-tert-bu-tylphenyl isothiocyanate; 2,6-di-tert-butyl-4-chlorophenyl isothiocyanate; 3-bromo-2,6-di-tert-butylphenyl isothiocyanate; 4-b1'orno-2,6-di-teIt-butylphenyl isothiocyanate; 6-chloro-2-methylphenyl isothiocyanate; 6-bromo-2-ethylphenyl isothiocyanate; 2-bromo-6-isopropylphenyl isothiocyanate; Z-tert-butyl-6-chlorophenyl isothiocyanate; 2-tert-butyl-6-chlorophenyl isothiocyanate; 2-tert-'butyl-4-chloro-6-methylphenyl isothiocyanate; 3-chloro-2-ethyl-6-isopropylphenyl isothiocyanate; 4-chloro-2-ethyl-6-isopropylphenyl isothiocyanate; 4'bromo-2-ethyl-6-isopropylphenyl isothiocyanate; 2-sec-buty1-3-chloro-6-ethylphenyl isothiocyanate; 4-chloro-2,3-dimethylphenyl isothiocyanate; 4-bromo-2,3-diethylphenyl isothiocyanate; 5-chloro-2,3-di-isopropylphenyl isothiocyanate; 6-bromo-2,3-di-isopropylphenyl isothiocyanate; etc.

Some of the halogenated diisothiocyanates which can be produced in the current present invention are:

4,4'-methylenebis 3-chloro-2,6-dimethylphenyl isothiocyanate) 4,4-methylenebis 3 -brorno-2,6-dicthylphenyl isothiocyanate) .raised to 190 C. under 4,4'-methylenebis(3-chloro-2,6-diisopropylpheny1 isothiocyanate) 4,4'-n1ethylenebis (2,6 -di-sec-butyl-3 -chlorophenyl isothiocyanate) 4,4'-methylenebis(3-bromo-2,6-di-sec-butylphenyl isothiocyanate) 4,4'-methylenebis 3-chloro-2-methyl-6-phenyl isothiocyanate) 4,4-methylenebis(3-bromo-2-tert-butyl-6-methylphenyl isothiocyanate);

4,4'-methylenebis 3 -bromo-2-ethyI-G-isopropylphenyl isothiocyanate);

4,4-methylenebis (2-primary-butyl-3-chloro-6- isopropylphenyl isothiocyanate);

4,4-methy1enebis(2-tert-butyl-3 -chloro-6-ethylphenyl isothiocyanate); etc.

Some of the halogenated hybrid diisothiocyanates which are formed in accordance with the present invention are:

3-chloro-2,6dimethy1-4,4'-methylenebisphenyl isothiocyanate; 3-bromo-2,6-diethyl-4,4-methylenebisphenyl isothiocyanate; 3-bromo-2,6-diisopropyl-4,4'-methylenebisphenyl isothiocyanate; 3-bromo-2,6-dinormal butyl-4,4-methylenebisphenyl isothiocyanate; 2-tert-butyl-3-chloro-6-methyl-4,4'-methylenebisphenyl isothiocyanate; 3-chloro-2-ethyl-6-methyl-4,4'-methylenebisphenyl isothiocyanate; 3-bromo-2-ethyl-6-isopropyl-4,4'-methylenebisphenyl isothiocyanate; 3-bromo-2-n-butyl-6-n-propyl-4,4'-methylenebisphenyl isothiocyanate; 3-bromo-2-n-butyl-6-tert-butyl-4,4'-methylenebisphenyl isothiocyanate; etc.

The starting aniline reagents which are used to produce the hindered halogenated isothiocyanates and diisothiocyanates are not listed inasmuch as the original aniline material is conventional. The halogenated and alkylated anilines used as reactants herein are prior-art compounds, and many are formed in accordance with the procedures set forth in my aforementioned c-opending patent application. Many of the compounds in this latter named group of compounds all have the same utility as each of the aforementioned groups of hindered isothiocyanates and diisothi-ocyanates. Moreover, the halogenated hindered isothiocyanates and halogenated hindered diisothiocyanates are all useful as insecticides and disinfectants.

The invention is further illustrated by, but not limited to, the following examples.

Example 1.2-tert-butyl-6-methylphenyl isothiocyanate One kilogram (6.12 moles) of 2-tert-butyl-6-methyl aniline and 2 milliliters of 25% sodium methoxide dissolved in methanol was placed in a 2-liter flask and was heated to 160 C. The contents of the flask were flushed with nitrogen. The addition of carbon disulfide was started and continued for two hours. The temperature was maintained at approximately 160 C. and after approximately 4 hours, additional carbon disulfide was added for another two hour period, and the temperature was dropped to C. After 10 additional hours, the above cycle was again repeated while maintaining the temperature at 165 C. The cycle was again repeated after another 24 hours at 160 C., and finally, after an additional 24-hour period, the cycle was again repeated while maintaining the temperature at C. The reaction was considered to be completed, but in order to insure completeness of reaction, the temperature was reflux conditions, and heated for approximately 8 hours.

The reactants had a turbid lemon color and did not assume the expected dark brown color. The reactants were distilled through a 16-inch column at 6-7 millimeters of pressure. The distillation fractions taken at various 12 On refractionation 801 grams of pure product was obtained. The final product had a boiling point of 169- 170 C. at 11.5 mm. Hg pressure, and a freezing point of 14 C. The index of refraction, D-line, at 25 C.

boiling point ranges are recorded in the following table. was 1.5740.

The final product had a melting point of 51-515 C.

and the laboratory analysis rendered the following composition:

Percent Carbon 70.41 Hydrogen 7.22 Sulfur 15.79

Analytical calculation produced a theoretical expectation of:

Percent Carbon 70.20 Hydrogen 7.36 Sulfur 15.62

The molecular structure was confirmed by infrared spectrum analysis.

Example 2.-4-tert-butyl-2,6-diethylphenyl isothiocycmare Eight-hundred grams (3.9 moles) of 4-tert-butyl-2,6- diethylaniline was placed in a 2-liter flask under a claisen head and a reflux condenser. A few milliliters of carbon disulfide was added and the mixture was heated to 180 C. The addition of carbon disulfide was then commenced at such a rate as to maintain a flask temperature of 180 to 200 C. The reaction was maintained at this temperature for approximately 85 hours, and a continuous evolution of hydrogen sulfide was noted for approximately the first 76 hours thereof, but the evolution of hydrogen sulfide virtually ceased after 76 hours.

The reaction products were distilled through a 48 Laboratory analysis of the reaction product indicated the following chemical composition:

Percent Carbon 72.66 Hydrogen 8.64 Sulfur 12.92

Analytical calculation indicated the following theoretical expectation for C H NS:

Percent Carbon 72.82- Hydrogen 8.56 Sulfur 12.96

The molecular structure was confirmed by infrared spectrum analysis.

Example 3.2-tert-butyl-6-ethylphenyl isolhiocyanatc Three hundred fifty-four grams (2 moles) of Z-tertbutyl-6-ethylaniline and 300 grams of carbon bisulfide were placed in a 1400 milliliter autoclave having a base stirrer and heated to 150 C. for 5 hours. After approximately 3 hours of heating, the pressure had risen from p.s.i. to approximately 250 p.s.i. It was partially vented and the heating was continued for an additional 2 hours. However all of the hydrogen sulfide which is formed in the reaction was not vented from the autoclave. The autoclave was then opened and the product which was in the form of a heavy mass, was removed and fractionated through a packed column at 10.5 millimeters pressure. Three distillation fractions were obtained as recorded in the following table.

TABLE Boiling Index of Fraction Point, Weight, Refraction Compound 0. grams at 25 C. (D-line) 118-124 5 1. 5363 2-tert-butyl-6-ethylaniline. 125-147 108 1. 5413 o. 147 116 1. 5841 2-tert-butyl-(l-cthylphenyl isothiocyanate.

inch packed column at about 12 mm. Hg pressure and 3 fractions were obtained.

The final product had a pale yellow color and did not crystallize with strong cooling. A laboratory analysis in- 13 dicated a sulfur content of 14.77%, whereas sulfur was calculated on the theoretical basis for C I-I NS of 14.62%. The relatively poor conversion rate was attributed to the fact that the hydrogen sulfide which formed *14 dropwisecondition and the mixture was heated at 200 C. for 16 hours.

The reaction products were fractionated through a 48 inch packed column at millimeters pressure and 3 in the reaction was not removed and this caused some 5 fractions were obtained as indicated in the following reversibility. table.

TABLE Boiling Index of Fraction Pomt, Weight, Refraction Compound 0. grams at C.

(D-line) 1 110-129 14 1. 5814 Combination of 2-tert-butylphenyl isothiocyanate and orthotertbutylaniline.

2 129-130 183 1.5968 2tert-butylpheny1isothiocyanate.

Example 4 26 diethylphenyl isolhiocyanme About grams of the residue was obtained and had 7 H the form of a tarry brown residue. The pure product F1!e hundred grams of 2,6'dlethyanlhne Was heatfid could not be made to freeze at temperatures as low as I O n I e p e a 2-l1ter flask under a reflux condenser to 180 C. Three 5 0 C, nd, therefore, n this respect, it is very similar hundred grams of carbon bisulfide was then added unt1l 25 to h original Starting 1 1i f the temperature was reduced to 150 C. Heating and rehi h it was d i d flu X1ng WEIS contlllued until the temperature age-1111 had A laboratory analysis indicated the following chemical arisen to 190 C. in approximately 2 hours. Heatlng was i i maintained at 190 C. with addition of carbon disulfide for approximately 33 hours. The reaction products were 30 Per ent distilled through a 48-inch packed column at 11 mllli- Carbon 68.78 meters pressure and five distillation fractions were ob- Hydrogen 7.07 tained as recorded in the following table. Sulfur 17.21

TABLE Boiling Index of Fraction Point, Weight, Refraction Compound 0. grams at 25 C. (D-line) 110430 46 1.5561 2,6-diethy1a11iline. 130435 21 1.5885 2,0-diethylaniline and aslight amount of 2,6-diethylphenyl isothioeyanate. 135-136 177 1. 5979 2,6diethylaniline. 135-136 104 1.5986 2,6-diethy1phenylisothiooyanate. 136-137 241 1. 5983 Do.

Twenty grams of fraction No. 4 was refluxed with 20 milliliters of concentrated ammonium hydroxide and 60 milliliters of methanol until the oil layer contained therein had disappeared. On cooling, 14 grams of white crystalline product in the form of fine needles and having a melting point of 195196 C. had precipitated.

A laboratory analysis indicated the following chemical composition:

Percent Carbon 69.07 Hydrogen 7.03 Sulfur 16.95

Analytical calculations for the thiourea, C H NS, with a molecular weight of 191.2 indicated the following theoretical expectation:

Percent Carbon -1 69.07 Hydrogen 6.85 Sulfur 16.76

Example 5.2-tert-buiylphenyl iso thiocyanate Four hundred fifty grams (3 moles) of ortho-tertbutyl aniline was placed in a 1-liter flask and heated to 200 C. Following this, carbon disulfide was added in a Analytical calculations for C H NS indicated the following theoretical expectations:

Percent Carbon 69.07 Hydrogen 6.85 Sulfur 16.76

Percent Carbon 74.07

Hydrogen 8.29

Example 6. 2,4-di-tert-butylphenyl isothiocyanate Four hundred ten grams (2 moles) of 2,4-di-tert-buty1- 1 aniline having an index of refraction at 25 C. of 1.5203, was charged in a liter flask which was fitted with a claisen head and a reflux condenser. The reactant was heated to 175 C. and carbon bisulfide was added. The reaction 16 Example 7.-2-tert-butyl-4-methylphertyl isothiocyanale Four hundred sixty-five grams (2.85 moles) of Z-tertbutyl-4-methylaniline having a boiling point of 120 to 121 C. at 11 mm. Hg pressure and an index of refracigg f zgzgg f f few 2 a 5 tion at 25 c. of 1.5368 (D-line), was placed in a 1-liter grab} yretarded the m g i 2 z z 586 f; flask which was, in turn, fitted with a claisen head and a ZZOOYC HOW r i s; gl S o d g reflux condenser. Carbon bisulfide was added in a dropthis g i i h d i 3 2 2% wise condition, and the reaction proceeded very rapidly to lower the flask i i 11480 e and was completed in 48 hours. During this time, a reture Wa maintah dpfor r t 1 8 L 10 action temperature of 172 to 200 C. was maintained. The further :ddition fecarbon f g ig j' q W1 d reaction temperature was maintained at 190 C. for an ucts were allowed to cool and then E r d n additional 24 hours to insure complete reaction. The reflask b cause of foamin nd i thrao action products were then distilled through a 48 inch e a 1 a packed column and the following fractions were obtained.

TABLE [At 115 mm. Hg pressure] Boiling Index of Fraction Point, Weight, Refraction Compound 0. grams at 25 C.

(D-liue) 1 110-126 13 1. 5421 Z-tert-butyl-A-nlctllylaniline.

2 126-136 14 1. 5544 2-tert-butyH-rnethylanilinc and 2- tert-butyl-4-111cthylpllenyl isothiocyanatc.

3 135-144 37 1.5773 2-tert-blltyl-4-mctllylphcnyl isotlliocyanate.

48 inch by 1 inch packed column where two fractions A sample of fraction No. 4 was chilled with thermomwere obtained. eter stirring. It became glassy at about C. and then TABLE [At 13 mm. Hg pressure] Boiling Index of Fraction Point, Weight, Refraction Compound 0 grams at 25 C. (D-line) 1 120-167 46 1. 5292 2,4-di-tert-butylaniline. 2 167-170 387 1.5702 2,4-di-tert-butylphenylisothiocyanate.

Fraction No. 2, containing the product, became glassy at about -10 C. but did not freeze. However, after onemonths time, the product did solidify and indicated a melting point of 47-50 C.

Laboratory analysis indicated the following chemical composition:

7 Percent Carbon 72.95 Hydrogen 8.74 Sulfur 12.98

Analytical calculations for C H NS indicated the following theoretical expectations:

Percent Carbon 72.82 Hydrogen 8.56 Sulfur 12.96

The molecular structure was confirmed by infrared spectrum analysis.

suddenly crystallized. The fraction had a melting point of 54 to 56 C. Laboratory analysis indicated a sulfur percent of 15.61% and a theoretical expectation of 15.62% when calculated for C H NS. The molecular structure was confirmed by infrared spectrum analysis.

Example 8.-2- ethylphenyl isothiocyanate One kilogram of 2-ethylaniline was charged to a 2-liter 3-necked flask which was fitted with a thermometer, a

dropping funnel and a reflux condenser. The Z-ethylaniline material was heated to C. and carbon bisulfide was added very slowly. During the addition of the carbon bisulfide, 4 pellets of potassium hydroxide were added and the reaction temperature was maintained at to 200 C. This reaction temperature was maintained for approximately 72 hours and the reactants were then distilled through a No. 3 column in 3 fractions.

17 I 18 Fractions 2 and 3 were co'oled to C. for approxi- The molecular structure was confirmed through infrared n1ately-8 hoursand then filtered. The cake portion on spectral analysis. I r 1 the filter which was washed with hexane comprised a 1 a snow White solid, 2,2'-diethylthiocarbide, having'a melt- I Example 1 ing point of 139-140 C. The filtrate was distilled through 1, 'sothwlcyanfate a 48 inch by 1 inch column at 11.5 millimeters of mercury Four hundred twenty-two grams of 2-tert-butyl-4,6-dipressure and 5 fractions were obtained. methylaniline was placed in a 2-liter 3-necked flask which TABLE [At 11.5 mm. mercury] Boiling Index of Fraction Point, Weight, Refraction Compound 0. grams at C. (Dame 112-114 32 1.6203 2-ethylphenylisothiocyanate. 114-115 26 1.6172 Do. 115-117 95 1 I 1.6175 Do. 117-11s 117 1. 6182 Do. 118-119 718 1. 6175 Do.

A laboratory analysis of the combined reaction product was fitted with a thermometer, a dropping funnel and a indicated the following chemical composition: reflux condenser. The flask was heated to 150 C. and Percent carbon bisulfide was added. The reaction was slow and Carbon 66.09 25 was not greatly accelerated by the addition of 0.5 gram Hydrogen 5.51 potassium hydroxide pellets. The reaction temperatures Sulfur 19.57 Was maintained for 175 hours at approximately 160 C.

with addition of carbon disulfide, as required. g gigfg gz gizggg gg mdlcated the 0110,- The product was then distilled through. a. 16 inch Percent 30 column at approxlmately 12.5 millimeters mercury pressure and 2 fractions were obtained. Carbon 66.22 Hydrogen 5.56 I Sulfur 19.64 TABLE The molecular structure was confirmed by infraraed spec- 7 I tmm analyslsr Fraction $3 1 13? gi e gr i s Compound Example 9.2 isopropylphenyl isoihiocyanate TWO hundred eighty-three grams of P opylani1ine 1 110-148 20 2-tert-buty1-4,fi-dimethylphenyl isothihaving an index refraction at 25 C. of 1.5462 was charged 40 2 148458 463 51 to a 1-liter flask having a dropping funnel, thermometer and a reflux condenser. The Z-isopropylaniline was heated I to 180 C. and carbon bisulfide Was added. The reaction was rapid and it was even greatly accelerated by the ad- Fraction 2 quickly solidified and melated at 98-100 C. dition of 0.5 gram potassium hydroxide pellets. The re- The laboratory analysis of the reaction product indiaction temperature was maintained for approximately 72 cated the following chemical composition: hours, but the reaction was believed to have been com- 2 Percent pleted in less than 72 hours. The reaction products were Carbon 71.40 then distilled through a 48 inch by /2 inch packed column Nitrogen 7.91 and 4 fractions were obtained. 50 Sulfur 14.64

AB [At 115 mm. Hg pressure] I I 7 V Boiling Index of Fraction Point, Weight, Refraction Compound 0. grams at 25 C. c

(D-line) 100-122 5 1. 5668 I J 122-124. 6 253 2-isopropylphenyl isothiocyanate. 124. 5425 90 D0.

Do. H

Laboratory analysis of the reaction product indicated -"Analytical calculation for C13H1'7NS indicated the followthe following chemical composition: ing theoretical expectation:

Percent Percent Carbon 67.61 Carbon 71.18 Hydrogen 6.39 Nitrogen 7.81 Sulfur 17.99 Sulfur 14.62

The molecular structure was confirmed through infrared Analytical calculations for C H NS indicated the followspectrum analysis ing theoretical expectation;

Percent Example ]1.2,4-a'.i(1,1-dimethylbutyl)phenyl Carbon 6776 isothiocyanate Hydrogen 6.25 One hundred ninety grams of 2,4-di-tert-hexylaniline Sulfur 18.09 and grams of bis'(methoxyethyl)ether were placed 19 in a 1-liter flask which was fitted with a claisen head and second for the first half hour, the reaction was very a reflux condenser. Approximately 100 grams of carbon rapid during this time and the temperature rose to 190 C. bisulfide was added and the reactant were heated to ap- The reaction temperature was then maintained at approxiproximately 160 C. The reaction was maintained at this mately 150 to 160 C. for approximately 48 hours to temperature for approximately 90 hours with further ad- 5 insure completeness of reaction. The reaction products dition of carbon disulfide' to insure complete reaction. were then distilled through a 48 inch column and the fol- The reaction products were then distilled through a 48 lowing 2 fractions were obtained.

TABLE Boiling Index of Fraction Point, Weight, Refraction Compound 0. grams at C. (D-line) 1 1.110-136 19 1.5440 Msopropyl-dmcthylnniliuc. 2 136-138 213 1.5963 Z-isopropyi-G-methylphcnyl isothiocyanatc.

inch packed distilling column at 11.5 millimeters of pres- Eighty grams of residue was obtained and indicated an sureand the following 3 fractions were obtained. index of refraction at 25 C. of 1.597. The residue was TABLE Boiling Index of Fraction Point, Weight, Refraction Compound 0. grams at 25 C. (D-line) 1 176-193 I 52 1. 5159 2,4-di-hexylani1ine. 2 193-195 72 1.5503 2,4-di-(1,l-di-methylbutybphenylisothioeyanate. a. 173-195 70 1.5508 Do.

Fractions 2 and 3 above, were recombined and rebelieved to be some of the reaction product, but distillafractionated under the same conditions and the two tion of this product was impossible because of the confollowing fractions were obtained. siderable amount of foaming.

TABLE Boiling Index of Fraction Point, Weight, Refraction Compound C. grams at 25 C.

(D-line) 1' 160-193 5 1. 5390 2,4-di-(1,l-dimethyibutyDphenyl isothiocyanate. 2'; 193-197 132 1.5515 Do.

Laboratory analysis 0f the reaction product indicated Laboratory analysis indicated the following chemical the following chemical composition: composition:

Percent Percent Carbon 75.09 55 Carbon 69.33 Hydrogen 9.57 Hydrogen 6.78 Sulfur 10,50 Sulfur 16.59 Analytical calculations for C H NS indicated the follow- Analytical calculations for n ls indicated the ing theoretical expectation: lowing theoretical expectation:

Percent Percent Carbon 75,19 Carbon 69.07 Hydrogen 9 63 Hy gen 6.85 Sulfur 10,65 S lfur 16.76

The molecular structure was confirmed by infrared spec- The Structure was confirmed by infrared p trum analysis. 7 7 V I trum analysis.

Example 12. 2-is0pr0pyl-6-11tethylpher yl isothiocyanate X P B- 2 1 y y Two hundred ninety grams of 2-isopropyl-6-methylphenyllsothmcyanate aniline was placed in a 3-necked l-liter flask which was SiX hundred twenty grams of y W fitted with a stirrer thermometer, a claisen head and a reaniline Was Placed a 3-llecked fl wh ch Was flux condenser. 0.3 gram of potassium hydroxide was fitted with a thermometer, a dropping funnel and a reflux added and the mixture was heated to C. Thereafter, condenser. Twenty-five milliliters of carbon bisulfide was carbon 'bisulfide was added at approximately 1 drop per 75 added. and the mixture was heated to C. Thereafter,

further carbon bisulfide was added, in addition to onehalf gram of potassium hydroxide. The reaction then proceeded at a very rapid rate and was completed in 44 hours. The reaction products were then distilled through a 48 inch by 1 inch packed column at 11.5 millimeters mercury pressure and 5 fractions were obtained as indicated in the following table.

22 Laboratory analysis indicated a sulfur percentage of 13.44% and chlorine of 14.92%. Analytical calculations indicated a theoretical expectation of chlorine at 14.79% and sulfur at 13.37%. The molecular structure was confirmed through infrared spectrum analysis.

Laboratory analysis of the reaction product indicated the following chemical composition:

Percent Carbon 73.60 Hydrogen 8.76 Sulfur 12.30

Analytical calculations for C H NS indicated the following theoretical expectation:

The molecular structure was confirmed by infrared spectrum analysis.

Example 14. 2 tert-butyl-S chloro-d methylphenyl isothz'ocyanate Five hundred twenty-seven grams of 2-tert-butyl-5- chloro-6-methylaniline and 270 grams of bis(2-methoxyethyl) ether were placed in a 2-liter flask which was fitted with a thermometer, dropping funnel and a reflux condenser. Four milliliters of sodium methoxide dissolved in methanol and 75 milliliters of carbon bisulfide were added and the mixture was gently heated for approximately 8 hours. The initial temperature was maintained at 90 C. and after the 8 hours, the temperature was raised to 105 C., for approximately 2 hours. Two grams of potassium hydroxide pellets were added but did not serve to catalyze the reaction to any extent. The heating was then continued at 120 C. for the next 6 hours. Thereafter, the heat was maintained at 190 C. and additional carbon bisulfide was slowly added. Thereafter, the temperature was lowered to 140 C. The 140 C. reaction temperature was maintained for approximately 70 hours and the reaction products were then distilled through a 16 inch column and the following fractions were obtained.

TABLE Example ]5.3-chloro-Z-methylphenyl isothio cyanate 1001 grams of 3-chloro-2-methylaniline was placed in a 2liter 3-necked flask fitted with a dropping funnel, a thermometer and a reflux condenser. Five milliliters of 25% sodium methoxide dissolved in methanol and approximately 25 milliliters of carbon bisulfide was added, and the mixture was heated under reflux at about 125 C. Thereafter, additional carbon bisulfide was added and when the additional amount reached approximately 100 milliliters, the mass became quite solid, despite atemperature raising of the flask to 150 C. 250 milliliters of bis- (ethoxyethyl)ether and 100 milliliters of glycol dimethyl ether were added, and most of the solid was dissolved. The temperature was maintained at aproximately 95 C. for 8 hours and then raised to 130 C. where an additional amount of carbon bisulfide was added. The temperature was then maintained at 127 for approximately 8 additional hours. Heat was then increased to 147 folan additional 12 hours and an additional amount of carbon bisulfide was added, but had little effect since very little gas evolution was noted. The 'reaction was continued at approximately 175 C. for an additional 16 hours. On cooling, a very considerable amount of solid crystallized which was distilled using a Vigreux distilling column at 7 millimeters pressure. The 3 following fractions were obtained.

Boiling Welght, P oilt,

Fraction grams Compound 142-148 26 A yellow solid mixture of 2-tert-butyl- 5ohlor0-6-methylaniline and 2-tertbutyl-5'chloro-G-methylphenyl isothiocyanate, having a melting point of 67-69 C Fraction #2 which contained some solid material was treated with 500 milliliters hexane and resulted in a very thin slurry which was placed in a freezing unit and maintained at -25 C. for approximately 2 hours. It 'was filtered and the cake was then washed with hexane and air dried, and resulted in a mass of 24 grams of 3,3'-di chloro-2,2'-dimethylthiocarbanilide, having a melting point of 169-170 C. The filtrate and fraction No. 3 above were combined and distilled through a 16 inch column and 5 additional fractions were obtained.

Fraction No. was analyzed after filtration and indicated a chlorine percentage of 19.30% and sulfur of 17.37%. Analytical calculations for C H CINS indicated an expectation of chlorine at 19.31% and sulfur at 17.46%.

Example 6.4,4-methylenebis(2,6-di ethylphenyl isothiocyanate) Five hundred twenty-four grams (1.64 moles) of 4,4- methylenebis(2,6-diethylaniline) having a melting point of 83 to 85 C. and 500 grams of diethylbenzene were placed in a 3-liter 3-necked flask fitted with a dropping funnel, a thermometer and a reflux condenser. The flask was purged with nitrogen and then heated to 150 C. Thereafter, car- 'bon bisulfide was added and the reaction was very rapid without the use of a catalyst, and was completed in 72 hours. The solution was filtered while still warm, and then allowed to cool. The solid was filtered off, washed with hexane and dried. The solid was then crystallized from tertiary butanol and had a melting point of 123 to 125 C.

The laboratory analysis indicated the following chemical composition:

Percent Carbon 69.69 Hydrogen 6.52 Sulfur 16.09

Analytical calculations for C H N S indicated the following theoretical expectation:

Percent Carbon 70.01 Hydrogen 6.64 Sulfur 16.25

Example 17.-4,4-methylenebis(2-tert-butyl-6-mefhylphenyl isothiocyanate One hundred fifty grams of 4,4'-methylenebis(2-tertbutyl-6-methylaniline) and 125 g. bis(methoxyethyl) ether were placed in a 1-liter, 3-necked flask, fitted with a thermometer, a dropping funnel and a reflux condenser. The flask was then purged with nitrogen and heated -to 150 C. Thereafter, carbon bisulfide was added and the reaction proceeded at a fairly rapid rate without the use of a catalyst. The reaction was judged to be completed in approximately 80 hours and the solution was filtered while still maintained at a warm temperature. Thereafter, the solution was allowed to cool, the solid filtered and washed with hexane and dried. The filtered powder was then crystallized from tertiary butanol and indicated a melting point of 104 to 105 C.

Laboratory analysis of the reaction product indicated the following chemical composition:

- Percent Carbon 71.12 .Hydrogen 7.11 Sulfur 15.03

Analytical calculations for C H N S indicated the following theoretical expectation:

Percent Carbon 71.04 Hydrogen 7.15 Sulfur 15.17

The molecular structure was confirmed by infrared spectrum analysis.

Reasonable variation and modifications are possible within the scope of the foregoing specification without departing from the nature and principle of my invention.

Having thus described my invention, what I desire to claim and secure by Letters Patent is:

1. A compound of the general formula is R where R R R R R R, R and R is a member selected from the class consisting of hydrogen, alkyl radicals up to 10 carbon atoms, chlorine, bromine, iodine and fluorine, and at least one of R R R and R is a tertiary alkyl radical of from 4 to 10 carbon atoms.

2. A compound of the general formula where R and R is a member selected from the class consisting of hydrogen and alkyl radicals of from 1 to 10 carbon atoms, and R and R are alkyl radicals of from 4 to 10 carbon atoms.

3. The compound Z-tert-butyl-6-methyl-4,4-methylenebis-(phenyl isothiocyanate) 4. The compound 4,4-methylenebis(2,6-diethylphenyl isothiocyanate 5. The compound 4,4-methylenebis(2-tert-butyl-6- methylphenyl isothiocyanate 6. The compound 4,4'-methylenebis(2-di-tert-butylphenyl isothiocyanate 7. The compound 4,4'-methylenebis(2-tert-butylphenyl isothiocyanate 8. A process for preparing and hindering the chemical reactivity of phenyl isothiocyanates, said process comprising introducing a tertiary alkyl radical of from four to ten carbon atoms onto a nuclear carbon atom of a primary aromatic amine in the ortho-position with respect to the amino radical of said aromatic amine, reacting in the absence of an oxidizing agent and at elevated temperatures the alkylated aromatic amine with carbon disulfide to form an unstable intermediate dithiocarbamic acid, and permitting the dithiocarbamic acid to break down to convert the amino radical to an isothiocyanate radical.

9. The process for producing hindered phenyl isothiocyanates which comprises contacting in the liquid phase an aniline compound having at least one tertiary ortho to theamino radical of said aniline with carbon disulfide within the temperature range of 80 C. to 300 C. in the absence of an oxidizing agent and for aperiod of time where hydrogen sulfide is no longer givenoff and thereby convert the amino radical to an isothiocyanate radical.

10. A process for preparing and hindering the chemical reactivity of a phenyl diisothiocyanate, said process comprising introducing a tertiary alkyl radical of from four to ten carbon atoms onto a nuclear carbon atom of a primary aromatic amine in an ortho-position With respect to the amino radical of said aromatic amine, reacting the alkylated aromatic amine With a formaldehyde yielding compound to produce an alkylated dianiline compound, reacting the alkylated dianiline compound with carbon disulfide in the absence of an oxidizing'agent to form an unstable intermediate dithiocarbamic acid, and

seam-1o permitting the dithiocarbarriic acid to break down to convert the amino radicals to isothiocyanate radicals. t

11. The process of making 4,4'-methylenebis(Z-tertbutyl-6-methylphenyl isothiocyanate) which comprises re- 5 acting 4,4 methylenebis( (2-tert-butyl-6-methylaniline) with carbon disulfide in the absence of an oxidizing agent.

References Cited UNITED STATES PATENTS CHARLES B. PARKER, Primary Examiner.

DALE R. MAHANAND, R. L. RAYMOND,

Assistant Examiners. 

1. A COMPOUND OF THE GENERAL FORMULA
 8. A PROCESS FOR PREPARING AND HINDERING THE CHEMICAL REACTIVITY OF PHENYL ISOTHIOCYANATES, SAID PROCESS COMPRISING INTRODUCING A TERTIARY ALKYL RADICAL OF FROM FOUR TO TEN CARBON ATOMS ONTO A NUCLEAR CARBON ATOM OF A PRIMARY AROMATIC AMINE IN THE ORTHO-POSITION WITH RESPECT TO THE AMINO RADICAL OF SAID AROMATIC AMINE, REACTING IN THE ABSNECE OF AN OXIDIZING AGENT AND AT ELEVATED TEMPERATURES THE ALKYLATED AROMATIC AMINE WITH CARBON DISULFIDE TO FORM AN UNSTABLE INTERMEDIATE DITHIOCARBAMIC ACID, AND PERMITTING THE DITHIOCARBAMIC ACID TO BREAK DOWN TO CONVERT THE AMINO RADICAL TO AN ISOTHIOCYANATE RADICAL. 